Pushbutton calculator



y 1969 E. 1.. TIBBETTS 3,446,433

PUSHBU'II'TON CALCULATOR Filed Dec. 20, 1967 Sheet 0:2

I l 4| I //0 90 INVENTOR. ERNEST L. TIBBETTS ATTORNEY May 27, 1969 E. L. TIIBBETTS 3,446,433

PUSHBUT'ION CALCULATOR F'iled Dc. 20. 19s? 250 FIG. 6

' INVENTOR. Ernest L. Tibbetts BY MC. QQ1

ATTORNEY United States Patent U.S. Cl. 235-145 Claims ABSTRACT OF THE DISCLOSURE The disclosure herein is of a pushbutton calculator comprising a plurality of columns of pushbuttons, each arranged in two groups and each pushbutton representing a numerical value, each pushbutton including a locking tab for engaging associated mechanical means for locking the button in a raised position or in a lowered position. The associated mechanical means includes a separate pivotable locking plate for each group of pushuttons in each column of pushbuttons, with each plate extending along the length of its group of pushbuttons in a column and having its upper edge formed so that it can be engaged by the locking tab of each pushbutton. Each pair of locking plates in a column is adapted to be spread apart by a clearing bar to free any pushbuttons which were in their lowered position and had been held thereby.

In a modification of the invention, each lockng plate is pivotally mounted and is pivoted by the clearing bar to free depressed pushbuttons.

Background of the invention The sliding bead abacus is widely used as a calculator in many parts of the world. However, this type of calculator has never been popular in this country, even though it is known that the abacus has merit both for its utility in teaching number concepts and for its simplicity and speed of operation. In order for the abacus to achieve .any wide use in this country, it would have to be introduced to our children, and, in order for this to happen, it is likely that the abacus must be somewhat more sophisticated without being any more expensive or more complex to operate. Such an abacus-type calculator is provided by the present invention Summary of the invention Briefly, the present invention comprises a plurality of columns of pushbuttons, each representing a numerical value and corresponding to one of the beads of the abacus, Each column of pushbuttons is separated into two groups for logic purposes. The same arrangement of columns of buttons and the same orientation of the buttons in each column is used as in the abacus. Thus, the apparatus of the invention is identical to an abacus as far as the user is concerned, except that he pushes buttons rather than sliding beads. Each pushbutton is constructed so that it can be held either in .a raised, non-operating position or in a lowered operating position representing the entry of its number in a calculating operation.

A separate locking plate is provided for each group of pushbuttons in each column of pushbuttons and two such plates extend along the length of each column. Each locking plate is mounted adjacent to its group of pushbuttons and includes a locking portion adapted to be engaged by each push-button when it is held in a lowered position. Clearing means is also provided for releasing pushbuttons held in their lowered position by the locking plates.

3,446,433 Patented May 27, 1969 Description of the drawing In the drawing:

FIG. 1 is a perspective view of the calculator of the invention;

FIG. 2 is a invention;

FIG. 3 is a side elevational view of one column of pushbuttons and the associated operating mechanism;

FIG. 4 is a plan view of a portion of the clearing bar and one column pushbutton locking mechanism before it is operated to release a pushbutton;

FIG. 5 shows the same structure as in FIG. 4 as they appear when a pushbutton is released;

FIG. 6 is a sectional view of a portion of a modification of the invention; and

FIG. 7 is a perspective view of a portion of the modified apparatus shown in FIG. 6.

plan view of a clearing bar used in the Description of the preferred embodiments The invention comprises a pushbutton abacus-type calculator 10 which includes a plurality of columns of pushbuttons 20, each of which is adapted to represent and display a numeral, with each column having an associated button-operating mechanism. The pushbuttons and associated operating mechanisms 26 (FIG. 3) are mounted in a housing 27 with an external portion 28 of each positioned in apertures in top plate 29 of housing 27. The pushbuttons in each column are arranged in two groups, with one group of two buttons spaced from a second group of five buttons, just as in the bead-type abacus.

The apparatus of the invention includes a separate operating mechanism 26 for each column of pushbuttons; however, only one such unit is shown and described. The operating mechanisms are oriented from front to rear of the housing and are suitably supported on the base of housing 27. Each mechanism includes fiat, horizontally oriented, elongated top plate 30 and bottom plate 40 spaced from each other. A plurality of auxiliary vertical support plates 50 are positioned parallel to each other between the top and bottom plates 30 and 40. A first thin, flat button-locking plate .60 extends parallel to the column of pushbuttons and is supported in slots in support plates 50 between top and bottom plates 30 and 40. Plate 60 is associated with the group of two buttons 20. A similar plate 70 is associated with the group of five buttons. The two plates 60 and 70 are aligned with each other, with a narrow space 71 between them and with their end surfaces 62 and 72 facing each other through this space. The plates 60 and 70 are spring-biased toward each other by means of springs secured to the plates and bearing against vertical spacer posts 50.

The top surfaces of the plates 60 and 70 are formed with looking tabs 90, one for each pushbutton, and each locking tab includes a sloping ramp surface 98 and a locking lip 99 at the lower end thereof. The ramp surfaces 98 of plate 60 have a negative slope, and those of plate 70 have a positive slope, as seen in FIG. 3.

The pushbuttons 20 themselves may be of any suitable type. A typical pushbutton as shown in FIG. 3 includes an enlarged external portion 28 secured to a stem 1 10 which is suitably supported for vertical sliding movement on plates 30 and 40. The stem is spring-biased so that it is normally urged to its raised, released position. Either the external portion 28 carries indicia, or such indicia may be positioned inside portion 28 which is made transparent. The stem 110 carries a projecting tab 12h which, normally and when the pushbutton is in its raised position, rests on the sloping ramp portion 98 of the associated locking tab When a pushbutton is depressed, the tab 120 bearing on the slope 98 forces the looking plate or out of position (dash lines FIG. 3) and permits the tab 120 to move beneath the locking lip 99 which is engaged thereby to hold the pushbutton depressed. The spring urges plate 60 or 70 back to its normal position, and thus causes lip 99 to hold tab securely.

Each column of pushbuttons has its associated operating mechanism 26 as described above, and a clearing bar is provided in operative relation with all of the mechanisms 26, particularly with all of the plates 60 and 70 for clearing depressed and locked pushbuttons. Clearing bar 130 comprises a generally flat rod having a handle 134 and comprising alternate narrow regions 136 and enlarged tapered regions 140 along its length as seen in FIG. 2. The clearing bar is oriented horizontally and extends from one side of the housing to the other, with each narrow portion 136 positioned in the space 71 between plates 60 and 70 of each operating mechanism 26. Handle 134 is accessible outside the housing. Suitable supports such as apertured plates or the like may be provided to maintain clearing bar 130 horizontal and in place.

In order to clear depressed pushbuttons 20, the clearing bar 130 is pressed inwardly and to the left, as seen in FIGS. 1, 4, and 5, so that its tapered portions 140 bear against and spread apart each set of locking plates 60 and 70 in each operating mechanism 26. This causes the locking lip 99 of a plate 60 or 70, which might be engaging a tab 120 on a button stem 110, to release the stem which would thus move upwardly to its released position.

In a modification of the invention shown in FIGS. 6 and 7, a modified pushbutton 198 and locking and clearing mechanism are used. The pushbutton in this instance includes a fixed post 200 which is mounted on the base 204 of the housing 27 and a slidable sleeve member 210, which is threaded on the post 200 and rests on a spring 220 which is also threaded on post 200 and is supported on the base 204. The post 200 carries on its upper end wall 230 a numeral 240 which .can be viewed through the closed end wall 250 of the slidable sleeve 210. Each slidable sleeve 210' of pushbutton 198 includes a tapered lip 260 which tapers outwardly from bottom to top to provide a top surface 270 which bears against the lower surface 279 of the top plate 29 of the housing under pressure from spring 220 to maintain the slidable sleeve of the pushbutton in its elevated position.

The lip 260, or rather its top surface 270, is also adapted to engage a locking plate 280 which serves to hold the pushbutton or sleeve 210 in its lower or depressed position. Locking plate 280 performs the function of plate 70 in FIG. 3, and a similar locking plate 280' aligned therewith performs the function of locking plate 60 in FIG. 3. A separate pair of looking plates 280' is provided for each column of pushbuttons, and each plate comprises an elongated sheet or strip of metal or plastic which extends along the length of its column of pushbuttons and is pivotally mounted about its lower edge 282 by pin 284 or the like secured to base 204 so that it can pivot toward and away from its column of pushbuttons. One or more springs 290 are also coupled between an upper portion, for example, the upper edge'298 of each locking plate 230 and 280 and the base 204 of the housing to provide a force urging each locking plate to pivot toward its pushbuttons. The upper edge 298 of each locking plate is curved to form a hook-like structure which can engage the locking lip 260 of each pushbutton sleeve 2 10.

In operation of this modification of the invention, when a pushbutton sleeve 210 is depressed, the tapered lip 260 forces its locking plate 280 to pivot in a counterclockwise direction away from the pushbuttons, as seen in FIGS. 6 and 7, so that the lip 260 can prass below the upper edge 298 of the plate 280- When the lip is below the upper edge of plate 280*, the springs 290 urge the plate 280 back in a clockwise direction toward the pushbuttons, and the lip 260 engages the upper edge of the plate as the sleeve 210 is urged upwardly by the spring 220, whereby the pushbutton is looked in place in its lowered position.

This embodiment of the invention utilizes a clearing bar 300 which comprises essentially a straight flat plate which extends horizontally parallel to the base of the housing and lies in a notch 302 in each plate 290. The bar 300 carries pairs of laterally extending tabs or cars 304 which are positioned so that each pair is close to or touches one locking plate 280 and one locking plate 280. It can be seen that, the bar 300 is moved to the left, as seen in FIG. 7, each pair of clearing tabs 304 causes its locking plates 280' to pivot to the left, whereby any pushbutton sleeves 210 which are depressed and held in place by the locking tab 260 are released and spring upwardly and assume their elevated position.

What is claimed is:

1. A pushbutton calculator comprising a plurality of columns of pushbuttons, each pushbutton representing a numerical value,

each column of pushbuttons being arranged in two groups,

each pushbutton including locking means [for locking the button in a raised position or in a lowered position, a separate auxiliary locking means for each group of each column of pushbuttons, each said auxiliary locking means extending along the length of its group of pushbuttons in each column and having a locking portion adapted to be engaged by the locking means of each associated pushbutton, whereby at least one pushbutton in each group in a column may be separately operated and locked in position, and

clearing means engaging all of said locking means and adapted to release all pushbuttons held in their lowered position by their locking means.

2. The apparatus defined in claim 1 and including spring biasing means associated with each said auxiliary locking means -for biasing each said auxiliary locking means to a normal position it occupies when all pushbuttons are in an elevated, non-registering position.

3. The calculator defined in claim 1 wherein each said separate auxiliary locking means comprises an elongated plate lying adjacent to a group of pushbuttons, the upperedge of each said plate being shaped so that it can engage and hold the associated pushbuttons when they are lowered.

4. The calculator defined in claim 1 wherein each said separate auxiliary locking means comprises an elongated plate lying adjacent to a group of pushbuttons, the upper edge of each said plate being shaped so that it can engage and hold the associated push buttons when they are lowered, each said plate having a lower edge pivotally mounted adjacent to its group of pushbuttons.

5. The calculator defined in claim 1 wherein each said separate auxiliary locking means comprises an elongated plate lying adjacent to a group of pushbuttons, the upper edge of each said plate being shaped so that it can engage and hold the associated pushbuttons when they are lowered, each said plate having a lower edge pivotally mounted adjacent to its group of pushbuttons, said springbiasing means urging each said plate to pivot about its lower edge toward its group of pushbuttons.

6. The calculator defined in claim 1 wherein said clearing means comprises a horizontal plate which engage each said separate locking means.

7. The calculator defined in claim 1 wherein said clearing means comprises a horizontal plate which includes separate tabs spaced apart along its length, each tab engaging one of said locking means, said horizontal plate being slidable through a tab for clearing the locking means to release lowered pushbuttons.

8. The calculator defined in claim 1 wherein said columns of pushbuttons are parallel to each other and each said locking means comprises a pair of locking plates pivotally mounted adjacent to and parallel to a column of pushbuttons, and said clearing means comprises a thin plate oriented horizontally and at a 90 angle to said columns of pushbuttons and said locking plates, said thin plate including a plurality of spaced-apart tabs, each of which engages one of said locking plates, said thin plate being slidably mounted so that it can pivot each locking plate and thereby release any pushbuttons held lowered by said locking plates.

9. The calculator defined in claim 1 wherein each said separate locking means comprises two aligned elongated plates lying adjacent to each column of pushbuttons, each of said two plates being shaped so that it can engage and hold a pushbutton in a lowered condition, said clearing means being adapted to operate all of said plates to release any lowered pushbuttons.

10. The calculator defined in claim 1 wherein each said separate locking means comprises two aligned elongated plates lying adjacent to a column of pushbuttons, each of said two plates being shaped so that it can engage and hold a pushbutton in a lowered condition, said clearing means comprising a thin plate positioned between the two aligned plates of each separate locking means and adapted to spread apart the two aligned plates of each locking means and thereby free any lowered pushbuttons.

References Cited UNITED STATES PATENTS 757,601 4/1904 Dement et al. 235-145 1,286,769 12/1918 Quentell 235-145 1,810,399 6/1931 Horni 235-27 2,265,626 12/1941 Butler 235-145 RICHARD B. WILKINSON, Primary Examiner. S. A. WAL, Assistant Examiner.

US. Cl. X.R. 235-27 

